 Tissues are groups of cells with a common structure (form) and function (job).  Four Main Tissues in the Body:  Epithelium  Connective tissue  Nervous tissue  Muscle tissue

 4 Major functions:  Protection from the outside world (skin)  Absorption (stomach and intestinal lining of the gut)  Filtration (kidney)  Secretions (gland formations)

 Closely attached to each other forming a protective barrier.  Always has one free (apical) surface open to outside the body or inside (cavity) an internal organ.  Always had one fixed (basal) section attached to underlying connective tissue.

 Has no blood vessels but can soak up nutrients from blood vessels in connective tissue underneath.  Can have lots of nerves in it (innervated)  Very good at regenerating (fixing itself)  i.e. sunburn, skinned knee, etc.

 By Shape  Squamous – flat and scale-like  Cuboidal – as tall as they are wide  Columnar – tall, column-shaped  By Cell Arrangement  Simple Epithelium – single layer of cells (usually for absorption and filtration)  Stratified Epithelium – stacked in layers (protection from abrasion (rubbing) – mouth, skin)

 Wraps around to cushion and protect organs.  Stores nutrients  Internal support for organs  As tendon and ligaments protects joints and attached muscles to bone and each other.  Runs through organ capsules and in deep layers of skin providing strength

 Ground substance – gel around cells and fibers  Fibers – provide strength, elasticity, and support  Cells

 Loose Connective Tissue  Dense Connective Tissue  Special Connective Tissue

 Areolar Connective Tissue – cushion around organs, loose arrangement of cells and fibers.  Adipose Tissue – Storehouse for nutrients, packed with cells and blood vessels.  Reticular Connective Tissue – internal supporting framework of some organs, delicate network of fibers and cells.

 Dense Regular Connective Tissue – tendons and ligaments, regularly arranged bundles packed with fibers running same way for strength in one direction.  Dense Irregular Connective Tissue – skin, organ capsules, irregularly arranged bundles packed with fibers for strength in all directions.

 Functions:  Provides strength with flexibility while resisting water, i.e. epiglottis, external ear, larynx.  Cushions and absorbs shock where bones meet i.e. intervertebral discs, joint capsules.

 Functions:  Provides framework and strength for body.  Allows movement.  Stores calcium (Ca)  Contains blood-forming cells.

 Functions:  Transports oxygen (O), carbon dioxide (CO2), and nutrients around the body.  Provides medium for immune response.

 Functions:  Conducts impulses to and from body organs via neurons.  Elements of Nervous Tissue:  Brain  Spinal Cord  Nerves

 Responsible for body movement.  Moves blood, food, waste through body’s organs.  Responsible for mechanical digestion i.e. chewing, tearing of food particles.

 Smooth Muscle – organ walls and blood vessel walls, involuntary, spindle-shaped cells for pushing things through organs.  Skeletal Muscle – large body muscles, voluntary, striated muscle packed in bundles and attached to bones for movement.  Cardiac Muscle – heart wall, involuntary, striated muscle with intercalated discs connecting cells for synchronized contractions during heart beat.